Vehicle seats typically comprise a metal structural frame and metal cushion-supporting springs supporting a cushion. Usually, the cushion-supporting springs consist of specially formed metal wires, which provide a suspension or cushioning effect. The cushion-supporting springs are linked to the metal structural frame by hook-shaped ends, which are coated with plastic. The plastic coating prevents a metallic contact between the cushion-supporting springs and the structural frame. Thereby, undesired squeak noises are avoided. An example for a vehicle seat of this type is disclosed in document WO2005/108160.
Furthermore, vehicle seats configured for detecting their occupancy state (i.e. “empty” or “occupied”) are known. Such seats are used, for example, in combination with seat belt reminder systems and for deactivating the passenger airbags if the seats are not occupied. Such seats generally comprise one or more pressure or proximity sensors. In document GB 1 467 769, load-sensitive switches are arranged on top of the cushion directly under a seat cover of the seat. In document FR 2 844 592 A1, the cushion-supporting suspension mats of the seat base and the seat back are used as the electrodes of a capacitive occupancy detection system. The electrodes are arranged below the cushion at the so-called “B-side” surface of the seat. In documents LU 91701 and U.S. Pat. No. 7,523,803, a tension sensor is arranged between the cushion-supporting spring and the structural frame to measure a mechanical tension between them or an elongation of the spring displacement.